English

Norms and Hermitian $\mathrm{K}$-Theory

K-Theory and Homology 2026-02-04 v1 Algebraic Geometry Algebraic Topology

Abstract

Over the past century, cohomology operations have played a crucial role in homotopy theory and its applications. A powerful framework for constructing such operations is the theory of commutative algebras in spectra. In this article, we discuss an algebro-geometric analogue of this framework, called the theory of normed algebras in motivic spectra. Specifically, we show that the motivic spectrum ko\mathrm{ko} representing very effective hermitian K\mathrm{K}-theory can be equipped with a normed algebra structure, and that the orientation map MSLko\mathrm{MSL} \to \mathrm{ko} respects this structure. The main step will be showing that the motivic infinite loop space machine is compatible with norms.

Keywords

Cite

@article{arxiv.2602.03021,
  title  = {Norms and Hermitian $\mathrm{K}$-Theory},
  author = {Brian Shin},
  journal= {arXiv preprint arXiv:2602.03021},
  year   = {2026}
}

Comments

An expository account of arXiv:2305.12684; Comments welcome!

R2 v1 2026-07-01T09:33:21.699Z